Ranking of Discussion Threads in a Question-And-Answer Forum

1. A computer-readable storage medium storing computer-executable instructions for controlling a computing system to score discussion threads in a question-and-answer form, each discussion thread having a plurality of posts with terms, the computer-executable instructions comprising: a component that provides a query; a component that identifies features of a discussion thread, the features including a combined post feature representing a collection of the terms of multiple posts of the plurality of posts of the discussion thread; a component that generates feature scores for the features, the feature score for the combined post feature indicating relevance of the terms of the collection to the query; a component that generates a relevance score for the discussion thread based on combining the feature scores for the discussion thread; and a component that presents the relevance score as an indication of the relevance of the discussion thread to the query.

2. The computer-readable storage medium of claim 1 wherein a feature of the discussion thread is a question that is a subject of the discussion thread.

3. The computer-readable storage medium of claim 2 wherein the question is derived from a subject field of an initial post of the discussion thread.

4. The computer-readable storage medium of claim 1 wherein a feature of the discussion thread is an initial post of the discussion thread.

5. The computer-readable storage medium of claim 4 wherein the feature that is the initial post contains terms of the body of the initial post but not the terms of the subject of the initial post.

6. The computer-readable storage medium of claim 1 wherein a feature of the discussion thread is an indication of whether the discussion thread includes an answer that has been verified.

7. The computer-readable storage medium of claim 1 wherein a feature of the discussion thread is based on clickthroughs for the discussion thread.

8. The computer-readable storage medium of claim 7 wherein the clickthroughs are generated by an external search engine.

9. The computer-readable storage medium of claim 1 wherein a feature of the discussion thread is based on recency of the discussion thread.

10. The computer-readable storage medium of claim 1 wherein the component that generates the relevance score combines the feature scores using feature weights learned by applying machine learning to training data.

11. The computer-readable storage medium of claim 1 including a component that ranks the discussion threads based on their relevance scores.

12. A computing system for scoring a discussion thread based on relevance to a query, the discussion thread being in a question-and-answer form, the discussion thread having a post that is the question of the discussion thread and a plurality of posts that are answers of the discussion thread, the computing system comprising: a computer-readable storage medium storing computer-executable instructions comprising: instructions that identify features of the discussion thread, the features including a question-based feature that includes terms relating to the posting of the question of the discussion thread and a combined post feature representing a collection of the terms of multiple answers of the discussion thread; instructions that generate feature scores for the features, wherein the feature score for the question-based feature indicates relevance of the terms relating to the posting of the question of the discussion thread to the query and the feature score for the combined post feature indicates relevance of the terms of the collection to the query; and instructions that generate a relevance score for the discussion thread based on combining the feature scores for the discussion thread; and a processor that executes the computer-executable instructions stored by the computer-readable storage medium.

13. The computing system of claim 12 wherein the question-based feature of the discussion thread is a question feature.

14. The computing system of claim 13 wherein the question feature is derived from a subject field of an initial post of the discussion thread.

15. The computing system of claim 12 wherein the question-based feature is a question post feature.

16. The computing system of claim 15 wherein the question post feature contains terms of the body of the post containing the question.

17. The computing system of claim 12 wherein a feature of the discussion thread is a clickthrough feature.

18. A method for ranking discussion threads of a question-and-answer forum, each discussion thread having a question post and a plurality of answer posts, the method comprising: providing a query; receiving a query that includes terms; for each of a plurality of discussion threads, identifying features of the discussion thread, the features including a combined post feature representing a collection of terms from multiple answer posts of the plurality of answer posts of the discussion thread, a question feature representing a question of the discussion thread, a question post feature representing terms of a question post of the discussion thread, and one or more features selected from a group consisting of an answer feature, a popularity feature, an authority feature, an importance feature, an internal clickthrough feature, and an external clickthrough feature; generating a feature score for each of the identified features; and generating a relevance score for the discussion thread based on a weighted combination of the feature scores for the discussion thread wherein the relevance score for the discussion thread is an overall score representing relevance of the discussion thread to the query; and ranking the discussion threads based on the overall scores of the discussion threads.

19. The computer-readable storage medium of claim 1 wherein the collection of terms includes terms from multiple answer posts of the discussion thread.

20. The computer-readable storage medium of claim 1 wherein the collection of terms includes terms from all the answer posts of the discussion thread.

21. The computer-readable storage medium of claim 1 wherein the computer-executable instructions further comprise a component that ranks a plurality of discussion threads based on their relevance scores.

22. The computer-readable storage medium of claim 21 wherein the computer-executable instructions further comprise a component that presents the ranking of the plurality of discussion threads.

23. The computing system of claim 12 wherein the computer-executable instructions further comprise instructions that rank a plurality of discussion threads based on their relevance scores and provide the ranking of the plurality of discussion threads.

24. The method of claim 18 further comprising outputting an indication of the ranking of the discussion threads.